quick update to my previous posts, Using the firmware for the ATTINY that was posted back in January on this thread I was able to get the power, HDD, clicker, etc. working. I was missing the low and high fuse values - something I didn't know anything about until working on this last night. I had some other minor issues with things like the SD card not being detected and hanging the system and the RP2040 not showing up as a USB device when connected to a windows PC, but I was able to sort those out as well. The SD card lines were bridged in 1 spot on the SOM header so reflowing solved that and same problem with the RP2040 but had to reflow the chip itself. still need firmware for that though!
Now I'm having a problem with the sound chip.
I noticed the S/PDIF port wasn't lit up so did some investigating. it's getting 5v where it should be on the line driver and there's continuity from the S/PDIF line on the CS4237 chip. I dug more into it, and I actually have no sound at all. The BIOS message says CS4237B Initialized on POST but cwdinit.exe says no crystal device detected even after inputting the environmental variables - SET BLASTER=A220 I7 D1 P330 T4. I tried UNISOUND to see if it finds the card, but it says no PNP devices detected - yes, I know the card should be initialized by the BIOS meaning no need for UNISOUND, but I had to try for my own sanity.
I checked over the pins on the chip and they are all solidly soldered to the board. Checked the pinout of both the chip and the board and found all locations that should have power and they all are getting their correct values.
Checked that the chip was oriented correctly as I've messed that up on another project in the past and it is indeed correct.
I also checked continuity on all the address lines and traced them back to the SOM. they all tested good. I didn't check A12 or A14 yet as they are on the other side of the SOM's header and didn't have time to pull it this morning, but I will later. I'm thinking they are probably ok though. Same with IRQ (IRQ7) and DMA (both DRQ1 and DACK1) lines. all seem to have continuity back to the SOM. also checked for bridges between all 100 pins and their neighbors.
Once again, I have to ask, AM I MISSING SOMETHING???
I know on the tinyLlama you had to flash an EEPROM to get it to work but that should be handled by the BIOS now as there is no EEPROM anymore, so I don't know what else to check. I'll check A12 and A14 tonight when I get home from work but the only other idea I have is to reflow all the chip legs, even though they have continuity, or replace the chip outright. It seems unlikely it's bad as it was brand new....well, NOS and never opened.
any CS4237B experts out there have any ideas?
What are the absolute bare minimum connections that the chip needs to be detected by DOS? I'm guessing address, data, IRQ and DMA lines and power but I certainly could be wrong!
If something was bridged on the input/output side like the wavetable header or even the speaker jacks on the back, could that cause the card to go into a protection mode or something?
I really just need to know WHERE to go next!
Aside from the RP2040 firmware, this is the last big issue I'm facing with my ITX llama build!